Nodes, cycles and paths

Imagine there are 10 sites with the identifiers A, B, C, D, E, F, G, H, I, and J. There is a link from

• I to J;
• B to C;
• E to F;
• C to G;
• G to H;
• H to G;
• H to I;
• C to A;
• A to B;
• D to E;
• F to D;
• F to J;
• J to I;
• B to D.

To better understand this scenario, please create a visual representation of the network by drawing it on paper. Now, let's name a group of sites a hub if each site of this group is reachable via links from any other site of this group. To make the definition clear, let's consider the following example:

Here, the sites $A$, $B$, and $D$ form a hub, since each site from this group is reachable to any other via links. Despite the fact that there is a link from $B$ to $C$, the site $C$ is not included to the hub because there is no link from $C$ to $B$ and hence neither of $A$, $B$, or $D$ is reachable from $C$.

Your task here is to find all hubs for the 10 mentioned sites and enter them in the field below. The expected output format is the following:

A B
C D
F G H

Here each line corresponds to a hub, and sites' identifiers are separated by spaces.